Portable crane



-Aprl 22,*1930. B. s'rcKFLETH Er AL I 1,755,798

Y PORTABLE CRANE i original Filed Feb. 1925 2 sheets-sheet 1 April 22, 1930. Y B. sTQckFLE-n-l ET Ap PORTABLE CRANE 2 Sheets-Sheet 2 Original Filed Feb. S9,Y 1925 Patentes Apr. 22, ieee BERGERl sI'oCKEIJETH, or BERRIER sBRrIIe-s, ARB FREDERICK w'. BURGER, oF NILEs,

s MICHIe-AN, -AssIGNoRs To CLARK TRUCTRACTO'R MICHIGAN, A CoRBoRATIoN or,A MICHIGAN COMPANY, E BATTLE CREEK,

i PORTABLE CRANE originai application Enea February aviszaseriaino. 7,946. Divided and this application mea April 17s,

19.28. Serial Qur invention relates to hoisting'mecha-A nism, such` as cranes and has vforone of its objects to provide improved hoistingmechanism especially adapted for vuse.l on a portable crane. Other objects of our-invention are to provide an improved hoisting mechanism in which the hoisting chain is movedV positively in either direction, regardless of whether or 'not it carries a load, and one in which the bight of the chain is always maintained taut so that any stretching of the chain is compensated for and it properly engages at all t-imes with the sheaves over which it Operates. Ve accomplish our objects as illustrated in the drawings and as hereinafter described. What we` regard asvnew is set forth in the claims.

In the accompanying drawings,-

Fig. 1 is a side elevationvof our improved:

crane attachment, showing it applied `to the front portion of va tractor to which it is 'at-v, tache'd, and which furnishes power to operate therhoisting mechanism, certain parts being broken away and some parts being in section; Fig. 2 is a diagrammatic view illustrating the arrangement 'of the hoisting chain with reference to the sheaves over which it runs; Fig. 3 is a front elevation of thecrane attachment and the tractor with which it is as* i other, theirvertical flanges being. on the in-V.

detail, being a cross.

sociated;

Fig.4 is an enlarged section on line t--i of Fig. 1;

Fig. 5`is an enlarged detail, being cross-.f

section on line 5-5 of Fig. but' showing partsthat are broken away in F 1g. 1; and

Y Fig. 6 is an enlarged detail, beingr a partialL section Aonline 6 6 of F ig. 4c.

Qur improved crane attachment andr the,V

hoisting mechanism thereof are of vthe ltype shown and described in our pending applicastood that our improved hoisting mechanism Friet;l

is not limited touse with such 'a vehicle, but

may be used in any situation to which it is 'I adapted." As shown in Fig. 1, the crane attachment comprises a yoke or U-shaped frame 7 disposed horizontally and adapted to be associated with the front of a tractor frame. Only the dashboard Sand front dirigible wheels 9 of the tractor are shown, as the tractor itself has nothing to do with our pres- Yent invention. The side members 10 of the attachment frame are adapted to be connectl ed with the tractor frame in any suitable way,

preferably such as that illustrated in .our

above-mentioned application.

The yoke 7 is supported at the sides of the tractor by caster wheels 11 mounted in yokes 12, asfshown in Fig. 3, said yokes being provided with ,verticalspindles journaled in sluit-A able bearings mounted in sleeves 13 at the op! posite ends of the intermediate portion ofthe yoke 7. As shown in Figs. 1 and 3, said sleeves are integral with the yoke.

Mounted on the central portion of the yoke 7 vis an upright mast or jib 14, asy shown in AFigs. 1 and 2, said mast being preferably composed oftwo parallel curved angle irons 15, 16 that are disposed oppositely to each side, as shown in Fig. 3. Said angle irons" are Ibraced by an upright curved plate 17 secured at itslower end ,to the yoke 7, as shown in said gure, and connected to said'angle irons by bolts 18.Y At the upper end of thel mast 14; is a transverse shaft 19, as shown in Fig. 1,"1which carries a sheavev 20. arranged between theV angle irons15, 16 andfadjacent to one of said angle irons, preferably the anglefiron 15,16", as shown in Fig. 3. In the suitable vbearings 23, 24 supported by the angle irons 15, 16, as shown in Fig. 3. Preferably the sheave 21 is secured to the shaft 22 by a pin 25 that passes through the hub 26 of said sheave and through said shaft. One end of the shaft 22 extends out through the bearing 24 and operatively engages a tubular shaft 27, best shown in Fig. 3, by which it is operatively connected with a shaft (not shown) on which a worm wheel 28, a p0rtion of which is shown in Figure 1,is nonrotatably secured. The worm wheel is enclosed in a housing 29 that is mounted on one of thesleeves 13, as shown in Figs. 1 and p3,

and in the lower portion of said housing isla worm 30 mounted on a shaft 31which in the illustrated construction is adapted to be alined substantially with a power take-off 'shaft on the tractor frame driven from the internal combustion engine of the tractor, as l described in my above-mentioned application. As the power take-olf shaft and its con- "nections with the engine have nothing to do with our present invention it has been deemed unnecessary to show or describe them herein. i The mast 14 also carries a bracket 32 located near its upper end, as shown in Fig. 1,

-said bracket being located between the angle iron members 15, 16 and being secured thereto by cross bolts 33, 34. Mounted on said bracket are two transversely disposed shafts 35, 36. The shaft 35 loosely supports an intermediate sheave 37 that is in the same vertical plane as the sheaves 2O and 21, and is provided with a laterally extending hub 38 onV which is loosely mounted a sheave 39, asbest shown'in Fig. 4. Between saidlsheaves 37 39V is a coiled spring 40., one end of which bears against a laterally projecting lug 41 carried by the sheave 37, and the other end of which bears against a laterally projecting lug 42 carried by the sheave 39, as best shownV in Fig. 6. By this arrangement the spring functions as a resilient power transmitting device by which power may be transmitted from the sheave 37 to rotate the sheave 39 in Y one direction, and, conversely, power may be applied by thesheave 39 to the sheave 37 to Y,rotate the latter in the opposite direction.

Y The shaft 36 carries an idler sheave 43, preferably smaller in diameter than .the sheaves 37 39and lying in the same vertical .plane as the sheave 39, as shown in Fig. 5.

All ofthe sheaves referred to are of the type adapted to be used in connection with a hoisting chainw44, their chain engaging surfaces being offsuch design as to engage the links of the chain and hold the chain against slip-` v page, as yclearly shown in Figs. 4 and 5. The' course ofthe hoisting chain 44 is best shown in Fig. 2, from which it will be seen that that end of the chain to which the load is attached,

andwhich preferably is provided with a hook ,e '45, or other convenient means for attaching it toa load, hangs pendent from the sheave 20 over which the chain runs.' It then passes .preferably connected to one of the angle iron members 15, 16, as indicated at 46. It Will be noted that the chain passes around sheave 39.` in the saine direction as that in which it passes around sheave 37, as clearly shown in Fig. 2.

The operation of the hoisting mechanism is as follows: To hoist the load, the sheave 21 is rotated in a clockwise direction as viewed in Fig. 2, as indicated by the arrow thereon, thereby drawing down the right-hand course of the chain as viewed in said figure, and paying out the left hand course thereof. The travel of the chain over sheave 37 causes said sheave to rotate in the same direction as the sheave 21, and through the spring 40 applies power to the sheave 39, which causes it also to rotate in the same direction. VConsequently the latter sheave takes up the chain paid out by the sheave 21 and delivers it at the righthand side of said sheave as viewed in Fig. 2, so that it hangs as a loop from the point 46. The bight of the chainbetvreen the sheaves 37, 39 and the sheave 2l is therefore always held taut. The sheave 43 serves to guide the chain so that it properly engages the sheave 39. In lowering the load all the sheaves are rotated in the opposite direction by its weight, but in lowering the chain when it carries no load the sheave 2 1 is rotated in a counterclockwise direction by power, and the consequent downward pull on the lefthand course of the chain as viewed in 2` positively rotates the sheave 39 in a counterclockwise direction, which, through the spring 40, rotates the sheave 37 in a like direction, thereby drawing'up the right-hand course of the chain and lowering the Vload sustaining end thereof. Our improved construction, therefore, provides for positively moving-the chain in either direction, regardless o f whether 'or not it carries a load, and always maintains the bight of the chain taut so that any stretching of the chain is conipensat'ed for and it properly engages the several sheaves at all times. Furthermore, there is no slack to hang down and interfere with the travel of the tractor, so that our improved construction is peculiarly suitable for use in connection with portable cranes. It will also be observed that by virtue of the substantially irreversible 'action of the worm wheel 28 and worm 30 (which prevents the worm wheel from driving back through the worm) these two elements serve to lock the hoisting mechanism with its loadin any elevated position.

ln the embodiment of our invention shown Vand described the sheaves are designed to receive and cooperate with a hoisting chain.

but we wish it to be understood that ourrinsuitable ieXible hoisting element designed to cooperate with supporting sheaves lwithout slippage,'and, therefore, the terni chain as herein used should be construed accordingly.

Also, while we have'sliown lour invention as f applied to ashop tractor'in which the hoisting mechanism is adapted toy be operatedby power derived from the engine of the tractor, itis to kbe understood thaty our improved `hoistingmechanism may beV operated by hand as well as by power, and that itV is'not limited Vto use with a tractor .as shown, but is adapted L the load vcarrying portion ofsaid chain operates, a ,driving sheave around which a bight of said chain runs and by .which said chain is driven, `and means actuated by the travel of-thefchain to maintain. both sides of said bight'ta ut Vrelatively to said driving sheave.

2. Al hoistingr mechanism comprising a hoisting chain, an. upper'fsheave over which the-loadcarrying portion of said chain operates, a driviiig'sheave around which abight of said chain runsand which said chain isdriven, and means .actuated by the travel ofthe hoistingchain in either direction -to maintain both sides oflsaid 'bight tant relay tively to said driving sheave.

V3. A hoisting mechanism comprising a hoisting chain, .an upper sheave over which the load carrying portion of said chain operates, a driving sheaveA around rwhich a @bightof said Vchain runs and by which said chain is driven, ,means actuated by the travel of rvthe chain to maintain both sides of 'said bight taut relatively to said 'driviiig'sheava and means for operatingsaid ,driving sheave.

4. A hoisting mechanism comprising a ,hoistingchaim an iippersheave over which the load carrying portionl of said chain operates, a driving sheave around which a bight of said chain runs and bywhi'ch saidchain is driven, an intermediatel sheave over which one course of thechain travels between said sheaves, Aand means actuated the rotationk of said intermediate sheave in; hoisting to maintain both sides of the bight oi said chain` tautrelatively to saidrdriving sheave.v

5. hoisting mechanism comprising a hoisting chain, aniipper sheave'over which the load carrying portion of saidichain operates, a` driving sheave around which a bight of said chain runs and which said chain is driven, an intermediate Visheave over which one coiirseof thech'ainftravels ybetween said l sheaves, and a sheave, over which a'bight of the chain travels, associated with said intersheave.

hoisting chain, an lupper sheave over which.v the load carrying portion of'said chain oper-A ates, a drivingsheave aroundwhich abight of said-'chain runs and by which said chain is driven, anintermediate sheave" over which one course of the chain travels between said sheaves, anda sheave, over whichv a bight of the chain travels, associated with said intermediate sheave and cooperating therewith,v

fto maintain bothl sides of thev bightof the ychain taut-relatively to said driving .sheave when'the chain travels in either direction.

7. A hoisting mechanism comprising a hoistingchain, an upper sheave overwhich the load carrying portion of said chain operates, a driving sheave around-.which a bight of said chain runs and by which said chain.Y is driven, an intermediate sheave over which one course o'f'the'chain'travels between said sheaves, a second intermediate sheave, over which a bight oi the chain travels, associated with and rotatable relatively to said first intermediate sheave and cooperating therewith to maintain both sides of the bight of the chain `taut relatively to said ,driving sheave when the chain travels in either direction, andl a spring interposed between said intermediate sheaves f-or transmitting power from one of said sheaves to the other.

V8. vA crane attachment comprising'a ,supporting Jframe, a mast carried thereby, a sheave'mounted on the mast',` a drivingsheave supported by said frame, a chain having Aa bight-thereof loopedv around saidY driving sheave and having -a yload carrying portion operating over said first-mentioned sheave,-

means for vdrivingsaid driving sheave, and `meansfor maintaining both sides of the bight ot said chain Vtaut relatively t-o said driving vv9. A crane attachment comprising a sup: porting frame, a mast carried thereby, a sheave mounted on the mast, a driving sheave supported Vby said frame, two intermediate sheaves, and a spring for transmitting power from either of said interdemiate sheaves to the other. y I

10. A crane attachment comprising a supporting frame, a mast carried thereby, a sheavemounted on the mast, a driving sheave supported by said frame, two intermediate sheavesfa spring for transmitting power from either of saidintermediate sheaves to the other, and a hoisting chain running over said rfirst-mentioned sheavel and one of said f intermediate sheaves and havingbights looped'aroiind said driving sheave and the,

other of saidintermediatesheaves. i' f 11. 'A hoisting mechanism `comprising a 'Y ates, a drivingsheave around which a bight of said chain runs and by which said chain is driven, means actuated bv the travel of the Achain to maintain ,both sides of said bight Vtaut ,relatively to said driving sheave, and

bightvthereoir' looped around said driving sheave Vand having a load carrying'portion operating over said iirst-mentioned sheave, worm gear mechanism for driving said driving sheave, and means for maintaining both sides of the bight of saidV chain taut relativelyY to said driving sheave.

13. A crane attachment comprising a supporting frame, a mast carried thereby, an upper sheave mounted on the mast, a driving.

sheave supported by said frame in alinement with said first mentioned sheave, a pair of intermediate sheaves between said upper sheave and said driving sheave, a laterally extending lug on one of said intermediate sheaves, a. spring bearing at one end on said lug, a laterally extending lug on the other of said intermediate sheaves on which the other end of said spring bears, whereby power is transmitted from either of said intermediate sheaves to the other.

14. A crane attachment comprising a supporting frame, a mast carried thereby, an upper sheave mounted on the mast, a driving sheave supported by said frame in alinement with saidupper sheave` a pair of intermediate sheaves between said upper sheave and said driving sheave, a laterally extending lug on one of said intermediateV sheaves, a spring bearing at one end on said lug, a laterally extending lugon the other of said intermediate sheaves on which the other end of said spring bears, whereby power is transmitted from either of said intermediate sheaves to the other, and a hoisting chain' running over said upper sheave and one of said intermediate sheaves and having bights looped around said driving sheave and the other of said intermediate sheaves. i

15. A crane attachment comprising a supv porting frame,'a mast carried thereby, an upper sheave mounted on the mast, a driving sheave supported by said frame in alinement with said upper sheave, a pair of intermediate sheaves between said upper sheave and said driving sheave, one of said intermediate sheaves being alined with said upper and driving sheaves, a laterally extending lug on said alined intermediate sheave, a spring bearing at one end on said lug, and a laterally extending lug on theother of said intermediate lsheaves on whiehthe other end of said spring bears, whereby power is .transmitted from either of said intermediate sheaves to the other. i

16. A crane attachment comprising a supporting frame, a mast carried thereby, an upper sheave mounted on the mast, a driving sheave supported by said frame in alinement with said upper sheave, an intermediate sheave between said upper .and driving sheaves and in alinement therewith, another intermediate sheave mounted coaxially with said iirst -mentioned intermediate sheave, a guide sheave supported by said frame in alinement with said latter intermediate sheave,.and a spring for transmitting power from either of said intermediate sheaves to the other. e Y l 17. A crane attachment comprising a support-ing frame, a mast carried thereby, an upper sheave mounted on the mast, a driving sheave supportedfby said frame in alinement with said upper sheave, an intermediate vsheave between said upper and driving sheaves and in alinement therewith, another intermediate sheave mounted coaxially with said Vfirst mentioned intermediate sheave, a guide sheave supported by said frame in alinement with said latter intermediate sheave, a spring for transmitting power from either of said intermediate sheaves tothe other, and a hoisting chain running over said upper shea-ve and said first-mentioned intermediate sheave and having bights looped around said driving sheave and the latter intermediate sheave, saidv guide sheave guiding the hoisting chain to said latter intermediate sheave.

18. A crane attachment comprising a frame adapted to be attached to a vehicle, a mast carried by said frame, a hoisting chain, a sheave mounted on the mast, Over which the yload carrying portion of said chain operates,

a driving sheave supported by said frame, around which a bight of said chain runs and by which said chain is driven, means actuated by the travel of the chain to maintain both sides of said bight taut relatively to said driving sheave, and means mounted on said frame and adapted to be driven from the vehicle for operating said driving sheave.

19. A crane attachment comprising a frame adapted to be attached to a vehicle, a mast carried by said frame, a sheave mounted on the mast, a driving sheave supported by said frame, two intermediate sheaves, a spring for transmitting power from either of said intermediate sheaves to the other, a hoisting chain running over said first-mentioned sheave and one of said intermediate sheaves and having bights looped around said driving sheave and the other of said intermediate sheaves, and means mounted on said frame and adapted to be driven from the vehicle for operating said driving sheave.

20. A crane attachment comprising a frame adapted to be attached to a vehicle, a

soV

mast carried by said frame, ahoisting chain, an upper sheave mounted on thermast, over which the load carrying portionof said chain operates, avdriving sheave around Which a y Y bight of said chain runs and by whichV it is driven, means, actuatedby the travel of the chain to maintain both sides of said bight taut relatively to said driving sheave, and worm gear mechanism moiinted on saidk frame and adapted to be driven from the vehicle for operating said driving sheave.

BERGER STOCKELETH. f FREDERICK W. BURGER. 

